1. Field of the Invention
This invention relates to a transponder as well as a reading and/or writing tool that can be used, for example, for testing and/or programming of the transponder.
2. Description of Related Art
Transponders are generally passive electronic circuits that comprise essentially an integrated circuit in which data can be stored, and an antenna that is electrically connected to the integrated circuit and that allows remote reading and/or recording of these data using a suitable reader. Transponders are used in the most varied applications, most often to identify, using the data they contain, an object to which they are attached or into which they have been inserted. The object is thus labeled by the transponder. Transponders are very often quite small in order to be inconspicuous or in order to be able to be inserted into objects in which available space is limited, such as, for example, into watch cases.
The transponder antenna generally consists of an induction coil made of a very fine copper wire. In the transponders of the prior art, the two ends of the coil are generally fixed, for example soldered, either on a small printed circuit on which the integrated circuit is likewise soldered, as described, for example, in International Application WO 96/07982, or directly on the integrated circuit. Such transponders are very delicate, mainly due to the risks of deformation of the coil and/or risks of breakage of the electrical circuit, especially near the solder, as a result of twisting of the copper wire. The position of the antenna relative to the integrated circuit thus must be as stable as possible. The antenna and the integrated circuit are very often kept together, for example in an electrically nonconductive resin, inside a box that protects the transponder against external stresses and prevents twisting, and thus breakage of the coil wires.
Transponders thus generally appear in the form of small electronic circuits, often rigid, with a size determined mainly by the external dimensions of the antenna that must exceed certain values in order to guarantee it sufficient gain.
In certain applications, however, it is difficult to discretely integrate such a transponder, precisely because of the size of the antenna. Thus, in the case of a watch, for example, the transponder is very often placed under the glass, on the periphery of the face, because this is essentially the only location allowing an antenna to be accommodated. Such an approach, however, cannot always be used, mainly for aesthetic reasons. Another approach is then to attach the transponder on the back of the watch, in which it can be easily concealed. The disadvantage of this variant is that since the back can very often be easily removed from the case of the watch, it becomes easy to destroy or tamper with the identification data of the watch that are contained in the integrated circuit by removing the transponder from the watch or by replacing the back of the watch by the back of another watch, for example.